TOEFL Listening: TPO-TOEFL听力TPO - O23127SK5WTH12RQR$

In the example about sports equipment, what does the professor imply about spending money on advertising? A. It is most effective just before holidays when people give gifts B. It may require quick decision making C. It is a waste, since many consumers select products based on their previous experiences D. It is better guided by good research than by good theories